<template>
    <div>
        <router-link tag='div' to='/' class='header-abs' v-show='showAbs'>
            <div class='iconfont header-abs-back'>&#xe606;</div>
        </router-link>
        <div class='header-fixed' v-show='!showAbs' :style='opacityStyle'>
            <router-link to='/'>
                <div class='iconfont header-fixed-back'>&#xe606;</div>
            </router-link>
            景点详情
        </div>
    </div>
</template>

<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  mounted () {
    window.addEventListener('scroll', this.handleScroll)
  }
}
</script>

<style lang='stylus' scoped>
@import '~styles/varibles.styl'
.header-abs
  position: absolute
  left: .2rem
  top: .2rem
  width: .8rem
  height: .8rem
  line-height: .8rem
  border-radius: .4rem
  background: rgba(0, 0, 0, 0.8)
  text-align: center
  .header-abs-back
    color: #fff
    font-size: .4rem
.header-fixed
    z-index: 2
    position: fixed
    top: 0
    left: 0
    right: 0
    height: $headerHeight
    line-height: $headerHeight
    height: $headerHeight
    background: $bgColor
    text-align: center
    color: #fff
    font-size: .32rem
    .header-fixed-back
        width: .64rem
        top: 0
        left: 0
        position: absolute
        text-align: center
        font-size: .4rem
        color: #fff
</style>
